Clinical impact of adjuvant chemotherapy in glioblastoma multiforme : a meta-analysis

IMPDH Inhibition Decreases TERT Expression and Synergizes the Cytotoxic Effect of Chemotherapeutic Agents in Glioblastoma Cells

IMP dehydrogenase (IMPDH) inhibition has emerged as a new target therapy for glioblastoma multiforme (GBM), which remains one of the most refractory tumors to date. TCGA analyses revealed distinct expression profiles of IMPDH isoenzymes in various subtypes of GBM and low-grade glioma (LGG). To dissect the mechanism(s) underlying the anti-tumor effect of IMPDH inhibition in adult GBM, we investigated how mycophenolic acid (MPA, an IMPDH inhibitor) treatment affected key oncogenic drivers in glioblastoma cells. Our results showed that MPA decreased the expression of telomerase reverse transcriptase (TERT) in both U87 and U251 cells, and the expression of O6-methylguanine-DNA methyltransferase (MGMT) in U251 cells. In support, MPA treatment reduced the amount of telomere repeats in U87 and U251 cells. TERT downregulation by MPA was associated with a significant decrease in c-Myc (a TERT transcription activator) in U87 but not U251 cells, and a dose-dependent increase in p53 and CCCTC-binding factor (CTCF) (TERT repressors) in both U87 and U251 cells. In U251 cells, MPA displayed strong cytotoxic synergy with BCNU and moderate synergy with irinotecan, oxaliplatin, paclitaxel, or temozolomide (TMZ). In U87 cells, MPA displayed strong cytotoxic synergy with all except TMZ, acting primarily through the apoptotic pathway. Our work expands the mechanistic potential of IMPDH inhibition to TERT/telomere regulation and reveals a synthetic lethality between MPA and anti-GBM drugs.

Nanogels as a Versatile Drug Delivery System for Brain Cancer

Chemotherapy and radiation remain as mainstays in the treatment of a variety of cancers globally, yet some therapies exhibit limited specificity and result in harsh side effects in patients. Brain tissue differs from other tissue due to restrictions from the blood-brain barrier, thus systemic treatment options are limited. The focus of this review is on nanogels as local and systemic drug delivery systems in the treatment of brain cancer. Nanogels are a unique local or systemic drug delivery system that is tailorable and consists of a three-dimensional polymeric network formed via physical or chemical assembly. For example, thermosensitive nanogels show promise in their ability to incorporate therapeutic agents in nano-structured matrices, be applied in the forms of sprays or sols to the area from which a tumor has been removed, form adhesive gels to fill the cavity and deliver treatment locally. Their usage does come with complications, such as handling, storage, chemical stability, and degradation. Despite these limitations, the current ongoing development of nanogels allows patient-centered treatment that can be considered as a promising tool for the management of brain cancer.

Zinc enhances temozolomide cytotoxicity in glioblastoma multiforme model systems

Temozolomide (TMZ) is an alkylating agent that has become the mainstay treatment of the most malignant brain cancer, glioblastoma multiforme (GBM). Unfortunately only a limited number of patients positively respond to it. It has been shown that zinc metal reestablishes chemosensitivity but this effect has not been tested with TMZ. Using both in vitro and in vivo experimental approaches, we investigated whether addition of zinc to TMZ enhances its cytotoxicity against GBM. In vitro cell viability analysis showed that the cytotoxic activity of TMZ was substantially increased with addition of zinc and this response was accompanied by an elevation of p21, PUMA, BAX and Caspase-3 expression and a decrease in growth fraction as manifested by low ki67 and lower colony formation. Analysis of GBM as intracranial xenografts in athymic mice and administration of concurrent TMZ and zinc yielded results consistent with those of the in vitro analyses. The co-treatment resulted in significant reduction in tumor volume in TMZ/zinc treated mice relative to treatment with TMZ alone. Our results suggest that zinc may serve as a potentiator of TMZ therapy in GBM patients.

Sulforaphane induces apoptosis and inhibits invasion in U251MG glioblastoma cells

In recent studies, sulforaphane (SFN) has been seen to demonstrate antioxidant and anti-tumor activities. In the present study, the viability inhibition effects of SFN in U251MG glioblastoma cells were analyzed by MTS. Morphology changes were observed by microscope. Apoptotic effects of SFN were evaluated by annexin V binding capacity with flow cytometric analysis. Invasion inhibition effects of SFN were tested by the invasion assay. The molecular mechanisms of apoptotic effects and invasion inhibition effects of SFN were detected by western blot and gelatin zymography. The results indicated that SFN has potent apoptotic effects and invasion inhibition effects against U251MG glioblastoma cells. These effects are both dose dependent. Taken together, SFN possessed apoptotic activity on U251MG cells indicated by increased annexin V-binding capacity, Bad, Bax, cytochrome C expression, and decreased Bcl-2 and survivin expressions. SFN inhibited invasion in U251MG cells via upregulation of E-cadherin and downregulation of MMP-2, MMP-9 and Galectin-3.

Radiation and concomitant chemotherapy for patients with glioblastoma multiforme

Postoperative external beam radiotherapy was considered the standard adjuvant treatment for patients with glioblastoma multiforme until the advent of using the drug temozolomide (TMZ) in addition to radiotherapy. High-dose volume should be focal, minimizing whole brain irradiation. Modern imaging, using several magnetic resonance sequences, has improved the planning target volume definition. The total dose delivered should be in the range of 60 Gy in fraction sizes of 1.8-2.0 Gy. Currently, TMZ concomitant and adjuvant to radiotherapy has become the standard of care for glioblastoma multiforme patients. Radiotherapy dose-intensification and radiosensitizer approaches have not improved the outcome. In spite of the lack of high quality evidence, stereotactic radiotherapy can be considered for a selected group of patients. For elderly patients, data suggest that the same survival benefit can be achieved with similar morbidity using a shorter course of radiotherapy (hypofractionation). Elderly patients with tumors that exhibit methylation of the O-6-methylguanine-DNA methyltransferase promoter can benefit from TMZ alone.

Temozolomide for high grade glioma

BACKGROUND

High grade glioma (HGG) is an aggressive form of brain cancer. Treatment of HGG usually entails biopsy, or resection if safe, followed by radiotherapy. Temozolomide is a novel oral chemotherapy drug that penetrates into the brain and purportedly has a low incidence of adverse events.

OBJECTIVES

To assess whether temozolomide has any advantage for treating HGG in either primary or recurrent disease settings.

SEARCH METHODS

The following databases were searched: CENTRAL (Issue 10, 2012), MEDLINE, EMBASE, Science Citation Index, Physician Data Query and the Meta-Register of Controlled Trials in October, 2012. Reference lists of identified studies were searched. The Journal of Neuro-Oncology and Neuro-oncology were handsearched from 1999 to 2012 including conference abstracts. We contacted neuro-oncologists regarding ongoing and unpublished trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) where the interventions were the use of temozolomide during primary therapy or for recurrent disease. Comparisons included no chemotherapy, non-temozolomide chemotherapy or different dosing schedules of temozolomide. Patients included those of all ages with histologically proven HGG.

DATA COLLECTION AND ANALYSIS

Two review authors undertook the quality assessment and data extraction. Outcome measures included: overall survival (OS); progression-free survival (PFS); quality of life (QoL); and adverse events.

MAIN RESULTS

For primary therapy three RCTs were identified, enrolling a total of 745 patients, that investigated temozolomide in combination with radiotherapy versus radiotherapy alone for glioblastoma multiforme (GBM). Temozolomide increased OS (hazard ratio (HR) 0.60, 95% confidence interval (CI) 0.46 to 0.79, P value 0.0003) and increased PFS (HR 0.63, 95% CI 0.43 to 0.92, P value 0.02), when compared with radiotherapy alone, although these benefits only appear to emerge when therapy is given in both concomitant and adjuvant phases of treatment. A single RCT found that temozolomide did not have a statistically significant effect on QoL. Risk of haematological complications, fatigue and infections were increased with temozolomide.In recurrent HGG, two RCTs enrolling 672 patients in total found that temozolomide did not increase OS compared to standard chemotherapy (HR 0.9, 95% CI 0.76 to 1.06, P value 0.2) but it did increase PFS in a subgroup analysis of grade IV GBM tumours (HR 0.68, 95% CI 0.51 to 0.90, P value 0.008). Adverse events were similar between arms.In the elderly, 2 RCTs of 664 patients found OS and PFS was similar with temozolomide alone versus radiotherapy alone. QoL did not appear to differ between arms in a single trial but certain adverse events were significantly more common with temozolomide.

AUTHORS' CONCLUSIONS

Temozolomide when given in both concomitant and adjuvant phases is an effective primary therapy in GBM compared to radiotherapy alone. It prolongs survival and delays progression without impacting on QoL but it does increase early adverse events. In recurrent GBM, temozolomide compared with standard chemotherapy improves time-to-progression (TTP) and may have benefits on QoL without increasing adverse events but it does not improve overall. In the elderly, temozolomide alone appears comparable to radiotherapy in terms of OS and PFS but with a higher instance of adverse events.

Implanted carmustine wafers followed by concomitant radiochemotherapy to treat newly diagnosed malignant gliomas: prospective, observational, multicenter study on 92 cases

OBJECTIVES

Study the feasibility and effectiveness of a treatment associated surgery, intraoperative chemotherapy (carmustine wafers), and concomitant radiochemotherapy (temozolomide) for the management of newly diagnosed, high-grade gliomas.

METHODS

Prospective multicenter study conducted in 17 French centers with a total of 92 patients with newly diagnosed malignant glioma treated by surgery, implanted Carmustine wafers (Gliadel(®)) followed by concomitant radiochemotherapy by temozolomide (Temodar(®)). Clinical, imaging, and survival data were collected to study toxicity-induced adverse events and efficacy.

RESULTS

A total of 20.6 % presented with adverse events during surgery, potentially attributable to carmustine, including 5 severe infections. Afterwards, 37.2 % of patients showed adverse events during radiochemotherapy and 40 % during adjuvant chemotherapy by temozolomide. We report a 10.5-month, median, progression-free survival and an 18.8-month median overall survival. No significant statistical difference was observed according to age, Karnofsky Performance Scale, or grade of the tumor. A prognostic difference at the limit of the significance threshold was observed according to the extent of the resection.

CONCLUSIONS

Multimodal treatment associating implanted carmustine chemotherapy and concomitant radiochemotherapy with temozolomide seems to yield better survival rates than those usually described when carmustine or temozolomide are used alone independently from one another. These interesting results were obtained without increased adverse events and would need to be validated during a phase 3 study.

Infrasound Sensitizes Human Glioblastoma Cells to Cisplatin-Induced Apoptosis

The development of nontoxic agents that can selectively enhance the cytotoxicity of chemotherapy is an important aim in oncology. This study evaluates the ability of infrasound exposure to sensitize glioblastoma cells to cisplatin-induced apoptosis. The infrasound was delivered using a device designed to replicate the unique infrasound emissions measured during external Qigong treatments. Human glioblastoma cell lines harboring wild-type p53 (U87) or mutant p53 (U251, SF210, and SF188) were treated in culture with cisplatin, infrasound emissions, or the combination of the 2 agents. Induction of apoptosis was quantified after 24 hours by flow cytometry following annexin V/propidium iodide staining. Infrasound emissions alone, delivered at moderate levels (~10 mPa) with dynamic frequency content (7-13 Hz), did not induce apoptosis, yet combining infrasound with cisplatin augmented the induction of apoptosis by cisplatin in all the 4 cell lines ( P < .05). Increased cellular uptake of the fluorophore calcein associated with infrasound exposure was quantified by fluorescence microscopy as well as flow cytometry, demonstrating increased cell membrane permeability. The 4 cell lines differed in the degree to which infrasound exposure increased calcein uptake, and these differences were predictive of the extent to which infrasound enhanced cisplatin-induced apoptosis. When exposed to specific frequencies, membrane permeabilization also appeared to be differentially responsive for each cell line, suggesting the potential for selective targeting of tissue types using isolated infrasonic frequencies. Additionally, the pressure amplitudes used in this study were several orders of magnitude less than those used in similar studies involving ultrasound and shock waves. The results of this study provide support for using infrasound to enhance the chemotherapeutic effects of cisplatin in a clinical setting.

Temozolomide and unusual indications: review of literature

Temozolomide (TMZ) was first known to be useful as a radiosensitiser in both primary brain tumours like glioblastoma multiforme and oligodendroglioma. Later, TMZ proved its efficacy in the treatment of melanoma. Multiple publications have demonstrated the benefit of TMZ in terms of efficacy and tolerance (used as mono-therapy or as adjuvant chemotherapy) compared to the "gold standard" treatment of this kind of tumours. Furthermore, several recent clinical trials have shown the particular importance of TMZ in other types of cancer. This publication deals with the use of TMZ in cancers which are not formal indications for TMZ (excluding glioblastoma multiforme, oligodendroglioma and melanoma). It also includes a necessary review of recent literature about the role of TMZ in the treatment of brain metastases, lymphomas, refractory leukaemia, neuroendocrine tumours, pituitary tumours, Ewing's sarcoma, primitive neuroectodermal tumours, lung cancer and other tumours.

Prognostic factors and survival in a prospective cohort of patients with high-grade glioma treated with carmustine wafers or temozolomide on an intention-to-treat basis

BACKGROUND

Patients with high-grade glioma can be treated with carmustine wafers or following the Stupp protocol. As far as we are aware, no scientific evidence has been published comparing the two treatments. The primary objective of this study was to analyse the survival of groups of patients with each of these treatment modalities. The secondary objective was to assess the influence of the usual prognostic factors on the patients in our hospital.

METHODS

A prospective cohort of 110 patients with single, supratentorial high-grade glioma treated by craniotomy and tumour resection was retrospectively studied. Half of the patients had carmustine wafers placed during this operation while the others (55) did not, the latter group receiving first-line systemic chemotherapy on an intention-to-treat basis.

FINDINGS

Patients treated with carmustine wafers had a median survival of 13.414 months compared with 11.047 in the group without implants (p = 0.856). For the overall cohort of patients, the following factors were found to influence survival: age (p < 0.0001), postoperative KPS score (p = 0.001), histological grade (p = 0.004), RPA class (p = 0.001), extent of resection (p = 0.002) and salvage surgery (p = 0.028).

CONCLUSIONS

In this prospective cohort of patients, analysed on the basis of intention-to-treat at the time of the first surgery, no statistically significant differences in survival were found between the two treatment modalities (carmustine wafers vs. first-line systemic chemotherapy). On the other hand, age, preoperative KPS, histological grade, and RPA class were confirmed to be prognostic factors in this cohort. Finally, the extent of resection was also found to influence survival.

Evolving strategies: future treatment of glioblastoma

Despite recent advances, there remains an unmet need for more effective treatments for newly diagnosed and recurrent glioblastoma (GBM). While currently available alkylator-based and antiangiogenic agents provide some efficacy, novel antiangiogenic and antiglioma treatments that provide enhanced efficacy with improvements in overall survival, the potential to overcome drug resistance and decreased treatment-related toxicity are still needed. Although VEGF-directed angiogenesis is critical during GBM pathogenesis, alternative proangiogenic and glioma-promoting pathways also play a key role in tumor progression. This article reviews the limitations of current GBM treatment, the importance of angiogenic signaling pathways in GBM pathogenesis and the preliminary results of novel antiangiogenic-targeted treatments being evaluated in GBM. Therapies that inhibit multiple glioma signaling pathways, including angiogenesis, have the possibility for further improving outcome in GBM and may represent the best option for increasing overall survival.

Early toxicity predicts long-term survival in high-grade glioma

Background:

Patients with high-grade gliomas are treated with surgery followed by chemoradiation. The risk factors and implications of neurological side effects are not known.

Methods:

Acute and late ⩾ grade 3 neurological toxicities (NTs) were analysed among 2761 patients from 14 RTOG trials accrued from 1983 to 2003. The association between acute and late toxicity was analysed using a stepwise logistic regression model. The association between the occurrence of acute NT and survival was analysed as an independent variable.

Results:

There were 2610 analysable patients (86% glioblastoma, 10% anaplastic astrocytoma). All received a systemic agent during radiation (83% chemotherapy, 17% biological agents). Median radiation dose was 60 Gy. There were 182 acute and 83 late NT events. On univariate analysis, older age, poor performance status, aggressive surgery, pre-existing neurological dysfunction, poor mental status and twice-daily radiation were associated with increased acute NT. In a stepwise logistic regression model the occurrence of acute NT was significantly associated with late NT (OR=2.40; 95% CI=1.2–4.8; P=0.014). The occurrence of acute NT predicted poorer overall survival, independent of recursive partitioning analysis class (median 7.8 vs 11.8 months).

Interpretation:

Acute NT is significantly associated with both late NT and overall survival.

Initial experience involving treatment and retreatment with carmustine wafers in combination with oral temozolomide: long-term survival in a child with relapsed glioblastoma multiforme

BACKGROUND

Glioblastomas occur infrequently in children, and the prognosis is better than for glioblastomas seen in adults. Aggressive treatment is justified in pediatric patients.

OBSERVATIONS

We present the case of a 6-year-old child with malignant posterior temporal glioma treated with surgery, radiotherapy, local chemotherapy with carmustine wafers, and oral therapy with temozolomide, both at initial diagnosis and at relapse 18 months later. After 6 years, the patient seems healthy with no focal neurologic signs, and imaging studies show no evidence of disease.

CONCLUSION

Multimodal therapy was found to have a very positive outcome for a child with malignant glioma.

Intralesional lymphokine-activated killer cells as adjuvant therapy for primary glioblastoma

Despite recent advances, median survival for patients with resectable glioblastoma multiforme (GBM) is only 12 to 15 months. We previously observed minimal toxicity and a 9.0-month median survival after treatment with intralesional autologous lymphokine-activated killer (LAK) cells in 40 patients with recurrent GBM. In this study, GBM patients were treated with adjuvant intralesional LAK cells. Eligible patients had completed primary therapy for GBM without disease progression. LAK cells were produced by incubating autologous peripheral blood mononuclear cells with interleukin-2 for 3 to 7 days and then placed into the surgically exposed tumor cavity by a neurosurgeon. The 19 men and 14 women had a median age of 57 years. Prior therapy included surgical resection (97%), partial brain irradiation (97%), gamma knife radiosurgery (97%), and temozolomide chemotherapy (70%). Median time from diagnosis to LAK cell therapy was 5.3 months (range: 3.0 to 11.1 mo). LAK cell treatment was well tolerated; average length of hospitalization was 3 days. At the time of this analysis, 27 patients have died; the median survival from the date of original diagnosis is 20.5 months with a 1-year survival rate of 75%. In subset analyses, superior survival was observed for patients who received higher numbers of CD3+/CD16+/CD56+ (T-LAK) cells in the cell products, which was associated with not taking corticosteroids in the month before leukopheresis. Intralesional LAK cell therapy is safe and the survival sufficiently encouraging to warrant further evaluation in a randomized phase 2 trial of intralesional therapies with LAK or carmustine-impregnated wafers.

High incidence of MGMT promoter methylation in primary glioblastomas without correlation with TP53 gene mutations

O(6)-methylguanine DNA methyltransferase (MGMT) reduces cytotoxicity of therapeutic or environmental alkylating agents. MGMT promoter methylation has been associated with TP53 G: C to A:T transition mutations in various types of cancers, and with poor prognosis in patients who did not receive chemotherapy. Mutations of TP53 are more frequent in secondary than in primary glioblastoma, thus the expected MGMT promoter methylation was low in primary glioblastoma. Glioblastoma patients with MGMT promoter methylation showed better response to chemotherapy based on alkylating agents and longer survival than patients without MGMT methylation. We examined 32 primary glioblastomas, treated with radiotherapy and surgery, for TP53 mutation by direct sequencing and MGMT promoter methylation by methylation-specific PCR. MGMT promoter methylation and TP53 mutations were detected in 72% and 31% of primary glioblastoma, respectively. Although not statistically significant, the frequency of TP53 G:C to A:T mutations were higher in cases with (26%) than without (11%) MGMT promoter methylation (p=0.376). MGMT promoter methylation had no impact on patient survival. Our data indicate that MGMT promoter methylation occurs frequently in primary glioblastoma, but does not lead to G:C to A:T TP53 mutations, has no independent prognostic value and is not a predictive marker unless glioblastoma patients are treated with chemotherapy.

Localized BCNU chemotherapy and the multimodal management of malignant glioma

BACKGROUND

Gliomas account for 42% of all primary CNS neoplasms and 77% of all malignant primary CNS neoplasms. Unfortunately the high-grade variant of gliomas, glioblastoma multiforme (GBM), is difficult to treat and generally considered incurable. Survival rates are generally poor, and neurological morbidity in the setting of disease progression is high. Fortunately, significant progress has been achieved in the past decade in our understanding of the molecular biology of this aggressive tumour histology and, as a consequence, there is renewed clinical trial activity in this area focused on improving quality of life, treatment-related morbidity and outcomes.

METHODS

A review of literature from June 2005 to June 2008 was conducted on multimodal treatment of malignant glioma (MG) patients, using specific search criteria in Medline, EMBASE, and BIOSIS. Abstracts from relevant US and European medical (cancer) meetings were also evaluated.

RESULTS

The established therapies for MG include surgery, radiotherapy (RT), and local or systemic chemotherapy. However, over the last 10 years only two chemotherapeutic agents have received regulatory approval for treatment of MG: polifeprosan 20 with carmustine (BCNU implant) and temozolomide (TMZ), an imidazotetrazine derivative of dacarbazine. More recent advances in the treatment of brain tumours have been in the development of multimodal approaches. Specific interest in the combination of BCNU implant and TMZ has arisen due to the demonstrable depletion by TMZ of the DNA repair enzyme responsible for resistance to a nitrosourea such as BCNU. Further interest in this combination stems from the observation that there is a difference in the time to peak effect for each agent. Additional emerging data suggest that multimodal therapy with maximal resection and BCNU implants, followed by adjuvant therapy with radiation and TMZ, is effective and well-tolerated in patients with initial high-grade, resectable MG.

CONCLUSIONS

The increasing body of efficacy data suggests that this combination of BCNU implants and TMZ within a multimodal treatment strategy including surgery and RT may provide an enhanced benefit compared with the use of either of these agents alone in select patients with high-grade glioma.

Epigenetic markers in human gliomas: prospects for therapeutic intervention

Gliomas represent the most common CNS cancers in adults. Prognosis for patients harboring malignant gliomas is particularly dismal and, despite current treatment strategies comprising surgery, radiotherapy and chemotherapy, the median survival time after diagnosis is still in the range of just 12 months. In recent years, there has been an increased effort to identify tumor biomarkers that can be used as diagnostic tools, or markers for predicting therapeutic response and prognosis. Investigation of genetic changes has identified several such markers that have shown some success in predicting the most effective therapy. In recent years, however, it has become apparent that the biology of many cancers of the CNS is determined not only by their genetic profile but also their epigenetic profile. Epigenetic biomarkers show great potential in effectively predicting patient prognosis and response to therapy. The eventual application of epigenetic profiling of tumors may help to indicate the most effective tailored therapy for individual patients.

Safety profile of carmustine wafers in malignant glioma: a review of controlled trials and a decade of clinical experience

BACKGROUND

Carmustine (1,3-bis [2-chloroethyl]-1-nitrosourea, or BCNU) wafers are approved for recurrent glioblastoma and newly diagnosed malignant glioma (MG). Based on considerable clinical experience and use in multimodal regimens, the safety of BCNU wafers needs a re-evaluation.

SCOPE

A review of literature from 1996 to February 2008 was conducted on the safety of BCNU wafer in MG patients using search criteria in Medline, EMBASE, and BIOSIS. Abstracts from relevant US and European meetings were also evaluated. Three Phase III (two were pivotal) and 26 non-Phase III studies met inclusion criteria. Overall incidence was estimated for each adverse event (AE), and data from individual studies were summarised as median (range) rates. Comparisons were based on consistent similarities or differences across overall incidence, median rate and range.

FINDINGS

BCNU wafer group AE rates from the two pivotal Phase III trials ranged from 4-23% for cerebral oedema, 4-9% for intracranial hypertension, 14-16% for healing abnormalities, 5% for CSF leaks, 4-5% for intracranial infection, 19-33% for seizures, 10% for deep vein thrombosis, and 8% for pulmonary embolus. There were no notable differences in AE rates between the two pivotal Phase III and 26 non-Phase III studies. For the non-pivotal studies, the overall incidence of AEs was low, ranging from 0.2% for intracranial hypertension to 9.6% for healing abnormalities. Healing abnormalities, intracranial infection, and seizures were the most consistently reported AEs, having been observed in 16, 12, and 11 studies, respectively. Rates of healing abnormalities appeared higher in recurrent than in newly diagnosed disease. There were no notable differences between BCNU wafer plus adjuvant treatment (e.g., temozolomide) and BCNU wafer alone, with the exception of haematologic toxicity.

CONCLUSION

This review of safety data for BCNU wafers provides reassurance that the AE rates reported in current treatment strategies including multimodal treatment approaches are comparable to those observed in the initial registration studies. The broad range of AE rates may reflect differences in the perioperative and postoperative management. Clinical experience suggests that strategies may exist to reduce the risk of complications.

Bevacizumab: A Treatment Option for Recurrent Glioblastoma Multiforme

Objective:

To review the available literature evaluating the effect of bevacizumab on progression-free survival when used in combination with irinotecan for recurrent glioblastoma multiforme (GBM).

Data Sources:

Searches of MEDLINE (1966-June 2008), the Cochrane Library. and International Pharmaceutical Abstracts (1970-June 2008) were conducted using the terms bevacizumab. irinotecan, and glioblastoma multiforme.

Study Selection And Data Extraction:

The search was limited to studies conducted in humans. All articles identified trom the data sources were evaluated. All clinical trials evaluating the efficacy and safety of bevacizumab in the treatment of recurrent GBM were included in the review.

Data Synthesis:

Hypoxia, mutagenesis, and the secretion of various growth (actors can all lead to production of vascular endothelial growth factor (VEGF), a proangiogenic growth factor, and angiogenesis in GBM. Neoplastic progression is dependent on angiogenesis, and anti-VEGF therapy has been successful in multiple disease states. However, there are currently no available anti-VEGF therapies approved tor treatment of GBM. Bevacizumab is a humanized monoclonal antibody that binds to and inhibits the activity of VEGF. When compared with data from clinical trials that use single chemotherapeutic agents in recurrent GBM, the addition of bevacizumab to cytotoxic chemotherapy, such as irinotecan, appears to improve progression-Iree survival in patients progressing on the standard of care, with a 6-month progression-free survival rate of 46%. Bevacizumab is well tolerated by most patients, with modest risk (11% tn Phase 2 trials) of venous thromboembolism.

Conclusions:

Although the combination of bevacizumab and irinotecan is producing positive results in patients with recurrent GBM, larger, randomized clinical trials need to be performed to determine the magnitude of the benefit from bevacizumab. Bevacizumab administered biweekly at a dose of 10 mg/kg in combination with irinotecan may improve progression-free survival.